Removal of phosphate by shale from Ivory Coast in homogeneous reactor and hydrodynamic conditions: influence of soluble species - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Clays and Clay Minerals Année : 2018

Removal of phosphate by shale from Ivory Coast in homogeneous reactor and hydrodynamic conditions: influence of soluble species

Résumé

Developing low cost and effective phosphate adsorbents is crucial to prevent eutrophication of natural waters. Here, phosphate removal by a natural and abundant shale from the Ivory Coast was investigated in both batch and column experiments with special attention devoted to understand the adsorption process. Batch experiments were carried out to assess the influence of initial phosphate concentration, sorbent dosage, contact time, and pH on phosphate removal. The phosphate removal efficiency increased with increased shale dosage while phosphate uptake decreased. Aqueous Ca, Mg, Al, and Fe species concentrations decreased in the presence of phosphate. Additionally, phosphate uptake strongly decreased with pH increases in the range 2–11, but then increased at pH 12. The kinetics were well described using a pseudo-second order model, and Langmuir adsorption isotherms were used for the equilibrium surface reactions. Adsorption to nanoparticles of goethite was hypothesized to be the major phosphate removal mechanism in the pH range 4–10. Column experiments with a flow rate of 1 mL min–1 and an initial phosphate concentration of 25 mg L–1 showed a breakthrough point at a V/Vp value of ~17, where V is the volume of phosphate solution added to the column and Vp is the pore volume. A V/Vp value of ~17 corresponded to a phosphate uptake of 0.17 mg/g, which was in agreement with the batch experiments. Column experiments revealed a strong correlation between the aqueous concentrations of Ca, Mg, Al, and Fe species and phosphate removal and, thus, suggest that phosphate removal by the shale occurred by aqueous dissolution/precipitation.
Fichier non déposé

Dates et versions

hal-02000244 , version 1 (30-01-2019)

Identifiants

Citer

D. Kpannieu, C. Ruby, L. Coulibaly, Mustapha Abdelmoula, M. Mallet. Removal of phosphate by shale from Ivory Coast in homogeneous reactor and hydrodynamic conditions: influence of soluble species. Clays and Clay Minerals, 2018, ⟨10.1346/CCMN.2018.064118⟩. ⟨hal-02000244⟩
42 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More